1. Field of the Invention
The present invention relates to a polymer composition excellent in fuel cost-saving properties and a conjugated diene based polymer for producing the polymer composition.
2. Description of the Related Art
As a rubber composition for automobile tires, a rubber composition containing a conjugated diene based polymer such as polybutadiene or a styrene-butadiene copolymer, and a reinforcing agent has been conventionally used.
For example, Patent Document 1 suggests a styrene-butadiene copolymer containing many vinyl bonds, and a polymer composition using the copolymer.    [Patent Document 1] JP 01-29802 B1